Influence of primary phase separations on the hydraulic reactivity of blastfurnace slag quenched by granulation

A description is given of the results of investigations into the influence of primary mineral phase separation during granulation on the hydraulic rea ctivity of granulated blastfurnace slags. Carefully controlled investigatio ns on 4 industrial and 30 synthetic granulated blastfurnace slags show that the formation of domains and primary mineral phases is dependent mainly on the chemical composition of the blastfurnace slags. Merwinitic segregation as well as merwinite as a primary phase can occur in all cases in which th e basicity CIS is greater than 1 and (C + M)/S is greater than 1.3. Melitit ic segregation and melilite as a primary phase are very rare in basic granu lated blastfurnace slag as the basicity is usually higher than 1. There is no generally detectable significant relationship between the primary minera l phase and the reactivity of granulated blastfurnace slag.